Question: $ { {2} \times \left[\begin{array}{r}{-1} \\ {-1} \\ {3}\end{array}\right] = {?} } $
To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{r}{2}\times{-1} \\ {2}\times{-1} \\ {2}\times{3}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{-2} \\ {-2} \\ {6}\end{array}\right]}$